[S-CG71] [EJ] 海洋底地球科学

[SCG71-13] CK16-05航海速報：伊是名海穴および伊平屋小海嶺における科学掘削－コア採取、地熱ツール検層とモニタリング装置の設置

*熊谷 英憲¹、石橋 純一郎²、野崎 達生¹、前田 玲奈¹、山田 泰広¹、猿橋 具和¹、許 正憲¹、CK16-05 乗船者一同 (1.国立研究開発法人海洋研究開発機構、2.九州大学)

キーワード：伊是名海穴、硫化鉱物の系統的採取、自然ガンマ線、長期モニタリング

The CK16-05 Cruise by D/V Chikyu was performed at the Izena Hole and Iheya Minor Ridge, in the middle Okinawa Trough from November 16th to December15th, 2016. Aiming to construct the genetic model of seafloor hydrothermal deposits, the subseafloor polymetallic sulfide ore body and relevant geology were investigated under an umbrella of Cross-ministerial Strategic Innovation Promotion Program (SIP). Throughout the cruise, systematic coring partly coupled with logging using a geothermal tool were conducted at the Hakurei Site, Izena Hole. Within the five of the eight sites, massive sulfide ore-bodies were successfully drilled and sampled. Owing to an improved sampling tool, a hydraulic piston-coring system modified to adjustable (short) penetration, the transition zones from sediments to ore bodies were continuously sampled without significant disturbances. The continuous profiles of natural gamma-ray together with borehole temperature and pressure were also obtained at the half of the holes. In the middle of the cruise, installation of a revised long-term monitoring apparatus equipped with sensors to monitor the secular variation of pressure, temperature, flow rate and precipitation weight within the apparatus on hydrothermal vents artificially made as Hole C9017A at the very vicinity of the last installation at the Hole C9017B, at Noho site, in the south of Iheya-Minor Ridge.

In this presentation, we report the preliminary results of operations conducted in the CK16-05 Cruise.